In a blog from 2010 where Charles Nurse first introduced ContentItems, he also talked about using the dnn_MetaData class. But I haven't really see it referenced anywhere else until today when I noticed Chis Hammond referenced it as being useless in his SimpleArticles source code.

I get the concept of it but it doesn't seem to have any real integration into DNN and I'm currently inclined to agree with Chris that it's not necessary. But I'm open to considering it if someone can explain how to use it to an advantage.